450 Formula Upper Extremity Practice Exam 2026 - Free Practice Questions and Study Guide

When the median nerve is injured, the pattern of finger flexion changes in a fist because the muscles that bend the index and middle fingers are paralyzed. Specifically, the flexor digitorum profundus muscles to the index and middle fingers (and the lateral two lumbricals that help flex the metacarpophalangeal joints) rely on the median nerve. Without their function, those two digits cannot flex at the joints needed to make a tight fist. The ring and little fingers can still flex because their flexors are largely supplied by the ulnar nerve. So, when a patient attempts to form a fist, digits two and three stay extended while digits four and five flex, producing the benediction gesture. This is a classic sign of median nerve injury.

The other signs are different tests or patterns: Tinel’s and Phalen’s signs are provocative tests for nerve compression at the wrist; Froment’s sign points to weakness of the adductor pollicis from ulnar nerve injury. The benediction sign uniquely reflects the loss of median-nerve–innervated flexion of the index and middle fingers during active fist formation.